Will it dim smoothly?

It is rated dimmable, but performance depends on the dimmer. Use a dimmer rated for LED loads; older incandescent-only dimmers often cause flicker or buzzing.

What fixtures is a T10 bulb for?

T10 is a long tubular shape meant for exposed-bulb fixtures: pendants, wall sconces, chandeliers and similar decorative fittings. It will not fit lampshades or enclosed fixtures sized for a round A19 bulb.

How bright is a 6W LED?

Roughly comparable to a 40W incandescent, though output varies by model. Check the lumen figure on the bulb if brightness matters for your room.

Is the clear glass different from frosted?

Yes. Clear glass shows the filament and gives a sharper, more sparkling light, while frosted glass diffuses it and reduces glare. Clear suits fixtures where the bulb is meant to be seen.

Does it work in an enclosed fixture?

LED bulbs run cooler than incandescent but still need airflow. In a fully enclosed fixture, check the bulb's rating; many LEDs are not approved for enclosed use.